Abstract <p>Whitefishes (Salmonidae: Coregoninae) are important components of the subarctic and subalpine aquatic ecosystems of the Palearctic. In most Siberian Arctic water bodies, they dominate by abundance. The most numerous and morphologically diverse are the pidschian-like whitefishes <i>Coregonus lavaretus</i> sensu lato, among which several forms/species with an unclear taxonomic status have been described. Most of the morphologically significantly different forms/species of whitefish live on the periphery of the entire range of the whitefish species. In most cases, genetic analysis of whitefish allows us to clarify the taxonomic status of disputed species and to analyze their phylogenetic relationships. However, there are cases when the results of morphological and genetic studies contradict each other, so additional methods of analysis are necessary. In our work, we attempted to analyze the issues of origin and differentiation of some of the most taxonomically complex forms/species of whitefish based on modern morphological and genetic methods of analysis.</p>